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Perennial herbs – can they make a contribution in high rainfall dairy pastures?

Joe Jacobs and Graeme Ward

Primary Industries Research Victoria, Department of Primary Industries, Warrnambool, Vic 3280. joe.jacobs@dpi.vic.gov.au

Abstract

This study determined the value of integrating chicory and plantain into dairy pastures. In October 2003, four brassica crops (turnips, Winfred, Hunter, Graza) and a C4 (millet) were spring sown alone or in combination with chicory and plantain (termed extras). The following autumn all treatments were oversown with Italian ryegrass and those plots without extras were then oversown with them. Spring sowing of extras resulted in higher herbage DM production in the following autumn, but lower herbage DM production in the subsequent spring compared to autumn sowing. Total DM production for the second year was higher for spring sown than autumn sown extras. From autumn to early spring of year 1, weed content was lower where extras were spring sown. Where extras were sown in spring, metabolisable energy was lower in late summer and also in the following spring. This study demonstrated that herbs sown with summer forage crops in spring can increase forage production during the following autumn and reduce weed ingression into newly sown pastures during the first year.

Key Words

Herbage production, chicory, plantain, metabolisable energy, weed suppression

Introduction

Perennial ryegrass is the primary species sown in dryland dairy pastures in southern Victoria. However, despite high annual dry matter (DM) production, the supply is uneven with up to 70% produced in spring. Although summer crops such as Brassica species can fill the summer feed gap, DM yields vary considerably. Furthermore, resowing ryegrass, which would be required in autumn may result in inadequate DM for grazing until late winter. The incorporation of perennial herbs such as chicory (Cichorium intybus L.) and plantain (Plantago lanceolata L.) may provide increased forage production particularly in summer and autumn. This study determined the value of integrating chicory and plantain into dryland dairy pastures in terms of their contribution to forage DM production and their influence on nutritive characteristics.

Materials and methods

This trial was conducted on a commercial dairy farm (38o 14’ S; 142o 55’E) in southwest Victoria. Treatment plots (50 m x 30 m) were established in October 2003 and sown to turnips (Brassica rapa L. cv Rival), Hunter (Brassica campestris L. x Brassica napus L.), Winfred (Brassica napus L.), Graza (a complex hybrid of Raphanus sativus L.) or millet (Echinochloa utilis Ohwi & Yabuno cv Shirohie). Each crop was sown alone or in combination with chicory (Grouse) and plantain (Tonic) (termed extras) with all treatments replicated four times in a randomised block design. In autumn 2004, all plots were oversown with Italian ryegrass and those plots without extras were then oversown with them. At each grazing, herbage DM on offer, botanical composition (sorted into sown components + weed and dead) and nutritive characteristics (metabolisable energy (ME), crude protein (CP) were determined. For herbage DM production, ANOVA was undertaken on a seasonal basis, whilst for botanical composition and ME REML was used (GenStat Committee 2003).

Results

In year 1, DM production over summer was higher (P<0.05) for millet and Winfred than Hunter or Graza (Table 1). In autumn, millet and turnips had lower (P<0.05) DM production than all other crops. Sowing extras in spring resulted in higher (P<0.05) DM production in the following autumn, but lower (P<0.05) DM production in the subsequent spring. Total DM production in the second year was higher (P<0.05) for spring sown extras. Both chicory and plantain contents (%DM) were higher (P<0.05) throughout the study when spring sown compared to autumn sown. From autumn in year 1 onwards, the ryegrass content was lower (P<0.05) where extras had been sown in spring and from autumn to early spring of year 1, weed content was lower (P<0.05) where extras had been spring sown (data not shown). From autumn to early spring in year 1, weed content for spring sown extras ranged from 4 to 8%, whilst for autumn sown extras from 17 to 25%. Spring sowing extras resulted in lower (P<0.05) ME values in summer of year 1 and also in late spring of year 2 (Figure 2).

Discussion

Spring sowing of extras led to additional autumn DM production in year 1 compared to autumn sowing of these species, with the increase primarily due to DM production from chicory and plantain which constituted close to

Table 1. The effect of different summer crops and spring or autumn sowing of extras on seasonal and total herbage DM accumulation (t DM/ha)

 

Sum-1

Aut-1

Win-1

Spr-1

Tot-1

Sum-2

Aut-2

Win-2

Spr-2

Tot-2

 

Crop

Hunter

4.87

2.03

2.51

5.63

13.02

2.62

0.51

3.08

3.04

11.27

Millet

6.63

1.41

3.22

5.56

15.30

2.67

0.60

2.97

3.03

10.79

Graza

4.93

2.24

2.60

5.75

13.25

2.50

0.39

3.18

2.84

11.19

Turnip

5.77

1.65

2.46

5.59

13.62

2.80

0.51

3.15

3.03

11.34

Winfred

6.59

1.97

1.87

6.17

14.45

2.89

0.52

2.94

2.88

11.38

l.s.d.

1.067

0.240

0.943

0.940

1.534

0.607

0.378

0.747

0.650

1.265

 

Sowing

Spring

5.50

2.18

2.48

5.42

13.47

2.87

0.51

3.11

2.89

11.63

Autumn

6.02

1.54

2.59

6.06

14.38

2.52

0.51

3.01

3.04

10.75

l.s.d.

0.676

0.152

0.596

0.595

0.970

0.384

0.239

0.473

0.411

0.800

Figure 2. Effect of spring (■) or autumn (▲) sowing of extras (chicory, plantain, red clover and white clover) on the metabolisable energy (MJ/kg DM) content of a mixed forage sward. l.s.d = 0.370.

70% of the sward at this time. Whilst spring sown chicory and plantain declined during winter and spring in year 1, the weed component remained less than 10% until late spring. This indicates that spring sowing of extras provided adequate ground cover to reduce weed invasion in the following autumn prior to establishment of the ryegrass. This study was sown with Italian ryegrass in autumn, however if a slower establishing perennial ryegrass had been used, it is likely that the DM contribution from herbs may have been greater as there would have been less competition from the ryegrass. Although chicory and plantain in the spring sown treatment declined to less than 15% of available DM a year after sowing (late spring 2004), it increased to 35% by autumn in year 2, thus still contributing to the total DM production of the sward. The lower ME values for the spring sown extras treatment in summer of year 1 and spring year 2 and are likely to be a result of both chicory and plantain entering their reproductive phase (Stewart 1996, Barry 1998). During late spring and summer, grazing rotation was based on the DM yields reaching particular targets. This may have led to a rotation interval that precluded adequate control of chicory and plantain reproductive development. This study demonstrated that herbs sown with summer forage crops in spring can increase forage production during the following autumn and reduce weed ingression into newly sown pastures. Maintaining nutritive value during late spring and summer may require more frequent grazing than normally used for ryegrass based pastures.

Acknowledgements

The authors wish to acknowledge the financial contributions of WestVic Dairy, Pyne Gould Guinness, Stephen Pasture Seeds and DemoDAIRY.

References

Barry TN (1998). The feeding value of chicory (Cichorium intybus) for ruminant livestock. Journal of Agricultural Science, Cambridge 131, 251-257.

GenStat Committee 2003. ‘GenStat Release 7.1.’(VSN International Ltd: Oxford)

Stewart AV (1996). Plantain (Plantago lanceolata) – a potential pasture species. In Proceedings of the New Zealand Grassland Association 58, 77-8

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